1. Field of the Invention
This invention relates to a charge coupling for an electric vehicle.
2. Statement of the Prior Art
Electric vehicles will find increasing use in the near future in view of environmental and energy concerns. As such, the problem of a battery charging must be overcome. In particular, a coupling for charging raises an important problem. A charge coupling includes a vehicle inlet or a vehicle connector installed in an electric vehicle and a supply connector or a power source connector connected to a power source on the ground. Charging work is carried out under relatively high voltages.
Accordingly, conduction should be commenced after a supply connector has been completely fitted to a vehicle inlet.
In actual charging work, an operator holds the supply connector and pushes it into the vehicle inlet. In this case, the operator can not confirm whether or not the supply connector is completely fitted to the vehicle inlet, from such an operation. If the operator can not visually determine incomplete fitting of the coupling, he can not confirm whether or not the coupling is in a suitable conduction state.
An opening of the vehicle inlet opens outwardly only when charging and otherwise is closed. If such closing is incomplete, water-proofing, dust-proofing and the like can not be effected properly. Accordingly, this is one of most important problems. Heretofore, a lid is rotatably attached to a vehicle inlet and is biased to a closed position by a spring so that the lid is closed under a state exclusive of a charging.
However, such a biasing force exerted by the spring can not positively lock the lid in the closed position. For example, the closed lid can be readily opened by an external force.
Even if the lid is pushed onto a rubber packing on the vehicle inlet, which serves to seal a clearance between the lid and inlet, by a spring biasing force, the lid is occasionally left half open.
Since the lid is closed by the spring biasing force when the external force is removed regardless of the operator's will, substances lodge between the vehicle inlet and the lid thereby resulting in incomplete closing.
Accordingly, it is very difficult to keep the lid in the complete closed position and to enhance reliability of the lid only by means of the spring biasing force.
It is necessary to prevent the coupling from leaking current and shorting a circuit due to rainwater between terminals upon charging on a rainy day. Thus, the supply connector is provided with a lid for closure upon non-charging and a rubber ring or the like is mounted on a mating portion of the coupling upon charging in order to prevent rainwater from entering into the mating portion.
In the prior art, water-proofing of the supply connector was effected by fitting a lid thereon and providing a mating portion of the coupling with a rubber ring after fitting.
However, upon charging, terminals in an end of the supply connector are exposed by opening the lid before the supply connector is fitted to the vehicle inlet. Also, rainwater may adhere to the exposed fitting face thereby causing leakage or short-circuiting between the terminals.
For convenience of explanation, terminals to be utilized in a conventional coupling will be explained below by referring to FIG. 33. FIG. 33 is a fragmentary longitudinal sectional view of a conventional supply connector.
As shown in FIG. 33, in the conventional coupling, a cavity 302 is formed in an inner housing 19a. The cavity 302 has an insertion port 303 for a terminal 310 at an end, a connector port 304 for a mating connector not shown at the other end, and a stopper 307 at a middle. The terminal 310 inserted in the cavity 302 is provided in its front end with a connection portion 311 for a mating terminal not shown and connected at its rear end to a cable 312 extending to a power source for charging. A cylindrical retainer 315 is mounted on the terminal 310. The retainer 315 is provided on its given positions with a lance 316 which can deflect elastically.
Upon inserting the terminal 310 into the cavity 302, the terminal 310 is inserted from the rear insertion port 303 through the middle portion to the front connection port 304. When the lance 316 of the retainer 315 is passing on the stopper 307, the lances 316 are deformed elastically and when it pass over the stopper 307, it recovers elastically to engage with a front edge of the stopper 307. At the same time, a shoulder 317 of the terminal 310 engages with a rear edge of the stopper 307. Then, the front end 311 of the terminal 310 is disposed in the connection port 304 of the cavity 302. At this time, insertion work is complete.
It is necessary to form a clearance corresponding to a height of the stopper 307 between the cavity 302 and the terminal 310 at an area from the front edge of the stopper 307 to the insertion port 304. The clearance induces a center gap in the terminal in the cavity 302. This center gap occurs if the cable 312 is bent or if an external force is applied to the terminal 310 in a direction perpendicular to the axis of the terminal 310, since the lance 316 is deformed elastically. Thus, the center gap impedes insertion of the mating terminal and will break the terminal 310 if the mating terminal is forced to be inserted into it.
In order to overcome this problem, the cavity 302 is formed into a rectangular shape in cross section and the terminal 310 is also formed into a corresponding rectangular shape in cross section. Such a rectangular shaped cross section enables both terminals to be centered but allows play in only one direction in which the stopper 307 is provided.
However, insertion work of the terminal 310 is troublesome since the terminal 310 must be inserted into the cavity 302 so that the lance 316 is directed to the stopper 307 in the cavity 302. Recently, a non-directive insertion method is required for terminals. Consequently, the terminal 310 and cavity 302 are formed into a circular shape in cross section and the stopper 307 is formed into an annular ridge to engage with the lance 316 in any circumferential direction. Although insertion can be effected smoothly, some problems will occur upon connecting of the mating connector, since a clearance is defined around the entire periphery of the connector portion of the terminal 310.
Further, for convenience of explanation, a connecting example of a conventional coupling will be described below by referring to FIG. 34. FIG. 34 is a explanatory view of a conventional charge coupling.
In FIG. 34, a vehicle inlet 1 is connected to a battery 4 and a supply connector 2 is connected through a flexible cable 23 to a charger 62. A distal end of the supply connector 2 is formed into a shape suitable for fitting into an inlet housing or guide cylinder 3. When they are interconnected, terminals in the inlet 1 and connector 2 are interconnected to be electrically conducted. In order to assist such fitting, the inlet housing 3 is provided on its outer periphery with spiral grooves 451 and a rotatable sleeve 452 mounted on the distal end of the supply connector 2 is provided on its inner periphery with pins engageable with the spiral grooves 451. Upon connecting the coupling, an operator holds the supply connector 2 with one hand so that the pins are engaged with the open ends of the spiral grooves 451 and rotates the sleeve 452 with his other hand. Then, the pins are guided by the spiral grooves 451 to advance the sleeve 452 and thus the supply connector 2 toward the vehicle inlet 1, thereby fitting the coupling.
However, a conventional coupling operation requires both hands to be used since one hand holds the supply connector 2 and the other hand rotates the sleeve 452. Thus, work efficiency is lowered.
In order to engage the pins of the sleeve 452 with the spiral grooves 451 to connect the coupling, the sleeve must be rotated by about one turn not-withstanding a slippery surface of the sleeve 452. This extends work time and lowers efficiency.
Since the outer periphery of the distal end of the supply connector is made of a metal material, it may injure a vehicle body if it contacts it by mistake.
Also, if the supply connector falls on the ground by mistake, it will be deformed at its distal end.
For convenience of explanation, means for draining water in an accommodating chamber which is provided in the vehicle body to accommodate the vehicle inlet will be described by referring to FIG. 35. FIG. 35 is a longitudinal sectional view of a conventional vehicle inlet. As shown in FIG. 35, an accommodating chamber 602 mounted on a vehicle body 200 is provided in its interior with a draining port 611. Water adhering to the interior of the chamber 602 flows down on the interior and is drained from the port 611 outside the chamber 602. In this construction, an inner wall 604 and opposite side walls 608 standing vertically in the accommodating chamber 602 will allow water to drain. However, since a ceiling wall 606 and a floor wall 607 are arranged horizontally, water adhering to the ceiling wall 606 does not flow to the inner wall 604 or side walls 608 and falls down directly on the floor wall 607, thereby wetting the vehicle inlet 1. On the other hand, water on the floor wall will be collected in an inner corner when the body is inclined on running, thereby wetting the vehicle inlet. Thus, since the vehicle inlet is readily wetted, exposed terminals in the vehicle inlet contact with water thereby causing leakage and short circuit.